1. Field of the Invention
The present invention generally relates to a seat occupant restraining apparatus or seat belt apparatus and, more particularly, to a seat occupant restraining apparatus for use in an automotive vehicle for restraining at least a driver or passenger in a seat assembly in the event of occurrence of a hazardous condition.
2. Description of the Prior Art
The hardtop model of an automotive vehicle is well known in which no generally vertically extending center pillar is employed on opposite sides of the automotive body structure. An example of the prior art seat belt apparatus used in the hardtop model for at least a driver's seat is illustrated in FIG. 29 of the accompanying drawings, reference to which will now be made for.
In FIG. 29, reference numerals 5 and 6 represent rear and front side doors on one side of the automotive body structure, for example, on the right-hand side thereof, and a seat assembly generally identified by reference numeral 1 is a driver's seat. As shown therein, the driver's seat assembly 1 includes a seat back 1a hingedly connected at a lower end to a seat cushion 1b so that the seat back 1a can be adjustably tiltable relative to the seat cushion 1b. The prior art seat belt apparatus includes a length of belt 3 having a first end anchored firmly to any appropriate fixture which is generally located laterally rearwardly and downwardly of the waist of an occupant of the seat assembly, for example, a rear side portion of the seat cushion 1a adjacent the front side door 6. The opposite, second end of the length of belt 3 is operatively connected to an automatic belt retractor as will be described in detail later. A lap strap 3a extends from the first end of the length of belt 3 across the lap of the seat occupant, a shoulder strap 3b extends from the lap strap 3a diagonally upwardly of an upper body part of the seat occupant and then over a right-hand shoulder of the seat occupant for holding the upper body part of the seat occupant against the seat back 1a, and a marginal strap 3c extends from the shoulder strap 3b and terminates at the second end of the length of belt 3. A portion of the belt 3 between the lap strap 3a and the shoulder strap 3b loosely passes through a latch plate which is removably connected to a buckle 7, said buckle 7 being secured to a rear side portion of the seat cushion 1a remote from the front side door 6 and opposite to that to which the first end of the belt 3 is anchored.
If, as shown by the phantom lines, the second end of the belt were operatively connected with a belt retractor with the marginal strap having been loosely passed through a loop plate 2' attached to a roof rail immediately above the side window, the marginal strap might obviously extend generally vertically across the side window and may constitute an obstruction to the field of view of the seat occupant. The presence of such an obstruction within the field of view of the seat occupant tends to deteriorate the feeling of openness uniquely provided for by the hardtop model.
Therefore, in the prior art seat belt apparatus such as disclosed in, for example, Japanese Laid-open Patent Publication No. 63-130450, published June 2, 1988, a portion of the belt 3 between the shoulder strap 3b and the marginal strap 3c loosely passes through a guide 4 mounted atop the seat back 1a, with the second end of the belt 3 operatively connected with a belt retractor 2 that is embedded in the rear side door 5. As a matter of general practice, the belt retractor 2 used in the prior art seat belt apparatus is provided with a lock mechanism by which the length of belt 3 can be freely retracted into and drawn out from the retractor during normal use and by which the length of belt 3 can be locked in position when a predetermined force of acceleration acts on the length of belt 3 and is subsequently transmitted to the belt retractor 2.
The prior art system wherein the belt retractor is employed within the rear side door has been found to prevent a possible problem in that, when the rear side door carrying the belt retractor is abruptly opened or closed, the acceleration acts on the locking mechanism built in the belt retractor to such an extent as to result in the locking of the belt retractor. In particular, when the belt retractor is consequently locked by the abrupt opening of the rear side door, the length of belt can be no longer pulled outwards from the belt retractor and it may happen that the rear side door will not open smoothly and/or the seat occupant may be restrained tight during the opening of the rear side door. On the other hand, when the belt retractor is consequently locked by the abrupt closure of the rear side door, the seat occupant may be insufficiently restrained and may therefore be required to reposition the belt.
Similar problems may occur when some closure members each hingedly supported for movement between opened and closed positions for selectively opening and closing a respective access opening, such as, for example, a front side door, a rear door, a engine hood, and a trunk lid, closure members other than the rear side doors, are opened or closed so abruptly and so roughly as to induce vibrations of a magnitude that may cause the locking mechanism to operate.